Abstract: In a preferred embodiment, a drill gas turbine motor in which the housing structure directs pressurized gas both radially inwardly and axially along the longitudinal axis of the elongated housing, against vanes arranged along a circumscribing surface of the revolvable (rotatable) rotor mounted within rotor space within the housing to effect rotation of the rotor, and a drivable shaft extending from an opening at one end of the housing, and a dampening-spring mechanism at an opposite end of the housing and rotor arranged to dampen pressure and movement of the rotor in a direction away from the end of the drivable shaft thereby reducing wear on bearings supporting the rotar at opposite ends thereof, together with brake mechanism for manually exerting braking pressure against the rotor, and key mechanism for locking the rotor in a non-revolvable state during change of chuck on the drivable shaft, and the drivable shaft having formed in a distal end thereof a female receptacle receivable of a male end of a chuck.